Ice-bags are only used in acute inflammation and in traumatic and other acute forms of synovitis. They undoubtedly help to soothe pain, and under some conditions have the antiphlogistic effect generally attributed to cold. Their first effect is to produce contraction of the blood vessels, with consequent anaemia. Without going into the complicated question as to how deep this influence extends or where the corresponding hyperaemia begins, I may mention here that Bier considers the hyperaemia resulting from the use of ice-bags as being passive hyperaemia, and we Swedes who often see face and hands "blue with cold" are inclined to agree with him.

Cold compresses (Priesnitz) should consist of a wet linen compress surrounded by a layer of waterproof material. Their effect is to soothe pain and by causing hyperaemia to promote absorption. These effects are due to their physical properties, and I have difficulty in believing in the value of the various salts which some people put in the water.